26 CFR §1.1561-2

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗

(a)Additional tax
1. (1)Calculation
  1. (i)In general. For the purpose of determining the amount, if any, of the additional tax imposed by section 11(b)(1) (the additional tax), the taxable incomes of all of the component members of a controlled group of corporations shall be combined to determine whether either of the income thresholds for imposing the additional tax have been attained.
  2. (ii)Special rules. For purposes of paragraph (a)(1)(i) of this section—
    1. (A)Component member means a corporation that is apportioned some part of any applicable tax bracket amount; and
    2. (B)Taxable income means the positive taxable income of a component member for its entire tax year (even if it was not a member of the group for each day of that tax year) that includes the same December 31st testing date, which is also applicable to the other component members of that same controlled group.
2. (2)Apportionment
  1. (i)General rule. Any additional tax determined under paragraph (a)(1) of this section shall be apportioned among such members in the same manner as the corresponding tax bracket of section 11(b)(1) is apportioned. For rules to apportion the section 11(b)(1) tax brackets among the component members of a controlled group, see § 1.1561-3(b) or (c).
  2. (ii)Apportionment methods. Unless the component members of a controlled group elect to use the first-in-first-out (FIFO) method described in paragraph (a)(2)(ii)(B) of this section, such members are required to apportion the amount of the additional tax using the proportionate method described in paragraph (a)(2)(ii)(A) of this section. These component members may elect the FIFO method by specifically adopting such method in their apportionment plan.
    1. (A)Proportionate method. Under the proportionate method, the additional tax is allocated to each component member in the same proportion as the portion of the tax-benefit amount that inured to a member from utilizing lower tax brackets bears to the amount of the group's total tax-benefit amount inuring to it from utilizing those lower tax brackets. The tax-benefit amount that inures to a corporation from using a particular tax bracket is the tax savings that such corporation realizes from having a portion of its taxable income taxed at the lower rate attributed to that tax bracket instead of the high tax rates to which it would otherwise be subject. The steps for applying the proportionate method of allocation are as follows:
      1. (1)Step 1. The regular tax (not including the additional tax) owed by a component member under a particular tax bracket is divided by the total tax owed by all component members under that tax bracket;
      2. (2)Step 2. The percentage calculated under Step 1 is multiplied by the total tax-benefit amount inuring to all the members of the group from their use of this tax bracket. This computed amount equals the portion of the group's tax-benefit amount that inured to such member from using its portion of this tax bracket;
      3. (3)Step 3. The amount determined under Step 2 is divided by the total tax-benefit amount, inuring to all the component members of the group from using all the tax brackets to which any component member's income was subject;
      4. (4)Step 4. The percentage calculated under Step 3 is multiplied by the amount of the group's additional tax. The amount determined under this Step 4 equals the amount of the additional tax apportioned to such member for that tax bracket; and
      5. (5)Step 5. If a component member is liable for regular tax (not including the additional tax) under more than one tax bracket, that member must calculate the amount of the additional tax apportioned to it with respect to each tax bracket. Accordingly, steps 1 through 4 must be applied for each tax bracket applicable to that member. The sum of all the apportioned amounts of additional tax from each tax bracket for which the member is subject is the total amount of the additional tax apportioned to that member.
    2. (B)FIFO method. Under the FIFO method, the first dollars of the additional tax are to be allocated proportionately to the members starting with the lowest tax bracket (that is, the first tax bracket), up to the amount of the tax benefit inuring to those members from using that tax bracket. Any remaining amount of additional tax is then allocated proportionately among the component members who use the next higher tax bracket, and so on, until the entire amount of the additional tax has been fully apportioned among the members. For example, the first $9,500 of the additional tax liability of a controlled group is apportioned entirely to the member(s) that availed themselves of the benefit of the 15 percent tax bracket.
3. (3)Examples. The provisions of this paragraph (a) may be illustrated by the following examples:
(b)Reduction to the amount exempted from the alternative minimum tax
1. (1)Calculation. The alternative minimum taxable incomes of the component members of a controlled group of corporations shall be taken into account in calculating the reduction set forth in section 55(d)(3) to the amount exempted from the alternative minimum tax (the exemption amount). For purposes of the preceding sentence, alternative minimum taxable income means the positive alternative minimum taxable income of a component member for its entire tax year (even if it was not a member of the group for each day of that tax year) that includes the same December 31st testing date, which is also applicable to the other component members of that same controlled group.
2. (2)Apportionment. Any reduction to the exemption amount shall be apportioned to the component members of a controlled group in the same manner that the amount of the exemption (provided in section 55(d)(2)) to the alternative minimum tax was allocated under section 1561(a). For rules to apportion the section 55(d)(2) exemption amount among the component members of a controlled group, see § 1.1561-3(b) or (c).
3. (3)Examples. The provisions of this paragraph (b) may be illustrated by the following example:
(c)Accumulated earnings credit. The component members of a controlled group of corporations are permitted to allocate the amount of the accumulated earnings credit unequally if they have an apportionment plan in effect.
(d)[Reserved]
(e)Short taxable years not including a December 31st date
1. (1)General rule. If a corporation has a short taxable year not including a December 31st date and, after applying the rules of section 1561(b) and paragraph (e)(2)(i) of this section, it qualifies as a component member of the group with respect to its short taxable year (short-year member), then, for purposes of subtitle A of the Internal Revenue Code, the amount of any tax-benefit item described in section 1561(b) allocated to that component member's short taxable year shall be the amount specified in section 1561(a) for that item, divided by the number of corporations which are component members of that group on the last day of that component member's short taxable year. The component members of such group may not apportion, by an apportionment plan, an amount of such tax-benefit item to any short-year member that differs from equal apportionment of that item.
2. (2)Additional rules. For purposes of paragraph (e)(1) of this section—
  1. (i)Section 1563(b) shall be applied as if the last day of the taxable year of a short-year member were substituted for December 31st; and
  2. (ii)The term short taxable year does not refer to any portion of a tax year of a corporation for which its income is required to be included in a consolidated return pursuant to § 1.1502-76(b).
3. (3)Calculation of the additional tax. A short-year member (as defined in paragraph (e)(1) of this section) for its short taxable year calculates its additional tax liability imposed by section 11(b)(1) only on its own income, and therefore the subsequent calculation of the additional tax liability with regard to the remaining members of the group will not include the income of this short-year member.
4. (4)Calculation of the alternative minimum tax. If a component member has a tax year of less than 12 months, whether or not such tax year includes a December 31st date, see section 443(d) for the annualization method required for calculating the alternative minimum tax.
5. (5)Examples. The provisions of this paragraph (e) may be illustrated by the following examples: